# Question 525 of 952 from exam 200-125: Cisco Certified Network Associate Exam

### Question

Which subnet mask would be appropriate for a network address range to be subnetted for up to eight LANs, with each LAN containing 5 to 26 hosts?

### Answers

### Explanations

Explanation

For a class C network, a mask of 255.255.255.224 will allow for up to 8 networks with 32 IP addresses each (30 usable).

To determine the appropriate subnet mask for a network address range to be subnetted for up to eight LANs, with each LAN containing 5 to 26 hosts, we need to calculate the number of host bits required for each LAN and the total number of subnets required.

First, we need to determine the maximum number of hosts per LAN. We are given that each LAN contains between 5 to 26 hosts, so we will use the highest number, which is 26. To represent 26 hosts in binary, we need 5 bits (2^5 = 32, which is greater than 26 but less than 32). Therefore, we need to reserve 5 bits for the host portion of the address.

Next, we need to determine the number of subnets required. We are told that we need to subnet the network address range for up to eight LANs. To represent 8 subnets in binary, we need 3 bits (2^3 = 8). Therefore, we need to reserve 3 bits for the subnet portion of the address.

To determine the subnet mask, we add the number of subnet bits and host bits together to get the total number of bits that need to be reserved. In this case, we need to reserve 8 bits (3 for subnets and 5 for hosts). The subnet mask with 8 bits set to 1 is 255.255.255.0 (11111111.11111111.11111111.00000000 in binary).

Option A, 0.0.0.240, has only 4 bits set to 1, which would allow for 16 subnets with up to 14 hosts per subnet.

Option B, 255.255.255.252, has 2 bits set to 0, which would allow for 2 subnets with up to 2 hosts per subnet.

Option D, 255.255.255.224, has 5 bits set to 0, which would allow for 32 subnets with up to 30 hosts per subnet.

Therefore, the correct answer is option C, 255.255.255.0, which has 8 bits set to 0, allowing for 8 subnets with up to 254 hosts per subnet.